Search found 3260 matches

by Lebowski
Aug 12 2011 4:19am
Forum: Motor Technology
Topic: Need help in driving brushless C6374 KV170
Replies: 19
Views: 2071

Re: Need help in driving brushless C6374 KV170

With a Kv of 170 you will get 3824 rpm. Thank you! So, if I want to get 1000 RPM I need to make about 1:4 belt reduction drive. One thing than I worry about is belt speed. I read a book about belt reduction drives, and there was said that typical belt speed does not exceed dozens of m/s. But I'm no...
by Lebowski
Aug 12 2011 3:25am
Forum: Motor Technology
Topic: Need help in driving brushless C6374 KV170
Replies: 19
Views: 2071

Re: Need help in driving brushless C6374 KV170

Typicalle engine speed depends on the Kv and the effective motor voltage. The effective motor voltage is the power supply (battery) voltage minus the current times the motor resistance. At 600 W / 24 V your current will be 25 Amps. With the specified motor resistance of 56 mOhm your effective voltag...
by Lebowski
Aug 12 2011 2:22am
Forum: E-Bike Non-hub Motor Drives
Topic: Nuvinci developer kits for cheap
Replies: 505
Views: 67774

Re: Nuvinci developer kits for cheap

amberwolf wrote:But it won't likely be $150, either. :lol:
yeah but with the smaller actuater it's going to be lighter and cost less to ship :D
by Lebowski
Aug 12 2011 1:54am
Forum: E-Bike Non-hub Motor Drives
Topic: Nuvinci developer kits for cheap
Replies: 505
Views: 67774

Re: Nuvinci developer kits for cheap

I just got word that probably around the middle of next year a similar kit will be available for the N360 :D
Since this is an easier-shifing hub the shift-actuator is going to be a lot smaller
by Lebowski
Aug 12 2011 1:38am
Forum: Motor Technology
Topic: Simple BLDC controller
Replies: 407
Views: 64970

Re: Simple BLDC controller

LOL nope. I played around a bit with code for my megasquirt2 a couple years ago. But now its time to do the real lerning. I will read and download that all in the morning. I don't have a programer yet but.... Can we build it too? I maybe in over my head but I always find my way to the top. I am don...
by Lebowski
Aug 12 2011 1:08am
Forum: Motor Technology
Topic: Simple BLDC controller
Replies: 407
Views: 64970

Re: Simple BLDC controller

OK so who wants to hold my hand and help me through the steps of programing the PIC18F2431 I will have it soon and I think I have everything on order I should need. So now is the time for me to read about programing and writing code. One of the reasons I got into this ebike building stuff is that I...
by Lebowski
Aug 11 2011 6:55am
Forum: E-Bike General Discussion
Topic: Pretend gas was gone tomorrow -
Replies: 28
Views: 1354

Re: Pretend gas was gone tomorrow -

let's see, I would build what comes down to the Bosch ebike system. So basically a crank motor (because of best efficiency under all conditions), pedal assist only (so not a full on motorbike, I really love the 'superman' feeling a pedal assist give). Battery, probably NiMH as lifetime is much longe...
by Lebowski
Aug 11 2011 2:42am
Forum: E-Bike Non-hub Motor Drives
Topic: Nuvinci developer kits for cheap
Replies: 505
Views: 67774

Re: Nuvinci developer kits for cheap

I contacted Fallbrook about shipping cost for one of these kits to Europe...
$150 shipping costs ! Rediculous ! This would basically double the price to $300 and
then I haven't counted the import tax etc yet.

No way I'm paying this much... pity :( :( :( :cry:
by Lebowski
Aug 10 2011 3:06pm
Forum: Motor Technology
Topic: 2-phase motor / controller idea any good?
Replies: 8
Views: 1117

Re: 2-phase motor / controller idea any good?

I'm thinking about a 4-pole 2 windings 90 degrees out of phase design, so the 4-phase you're talking about.. bit of confusion
about nr of connections versus nr of coil, sorry 'bout that
by Lebowski
Aug 10 2011 10:38am
Forum: Motor Technology
Topic: 2-phase motor / controller idea any good?
Replies: 8
Views: 1117

2-phase motor / controller idea any good?

I've been wondering about a new motor/controller idea I have... Most (all?) of our BLDC motors are 3 phase motors. 3-phase is used in the mains power distribution network because you don't need a return wire for the ground, in essence the currents in the 3 phases cancel each other out such that no c...
by Lebowski
Aug 10 2011 7:46am
Forum: E-Bike General Discussion
Topic: perspex plastic vs ping battery ?
Replies: 13
Views: 1515

Re: perspex plastic vs ping battery ?

maybe it's easier to use Acryllic glass ? It has a high melting temp (190C, 375F) and is easier to saw / drill than perspex.
by Lebowski
Aug 08 2011 8:45am
Forum: Motor Technology
Topic: Re-wind of a turnigy 80/100 (Now-tutorial w/Video)
Replies: 421
Views: 82548

Re: Re-wind of a turnigy 80/100 (Now-tutorial w/Video)

Hello! I'm a first time poster here but have been reading this forum for quite a while now (and specially the non-hub and motor technology sub-fora) I was wondering if anyone had tried rewinding a turnigy with copper foil instead of wire. Something like 0.1mm thick and as close to 16mm wide as poss...
by Lebowski
Aug 04 2011 2:07am
Forum: Motor Technology
Topic: Inductance What is it what does it do? Collosus has 8uH!
Replies: 308
Views: 31834

Re: Inductance What is it what does it do? Collosus has 8uH!

IN fact I tell you what I will wind it in such a way that I test the same lengh of wire with 3 turns with one and two strands.... So I will still have the two peices of wire hooked to the meter with one set of turns or 2 parallel sets of turns. What I would do is make two measurements, both with th...
by Lebowski
Aug 04 2011 1:31am
Forum: Motor Technology
Topic: Inductance What is it what does it do? Collosus has 8uH!
Replies: 308
Views: 31834

Re: Inductance What is it what does it do?

OK SOOOOOOOOOOOOOOOOOOOOOOOOOOOO BIIIIIIIIIIGGGGGGGGGGG NEEEEEEEEEEWWWWWWWWWS. Collossus has such low inductance it midas well not have any (well ok almost) I got the first cheep inductance meter today and here is some findings.... OH BTW you guys rewinding motors that are hard to control you would...
by Lebowski
Aug 04 2011 1:13am
Forum: Motor Technology
Topic: Inductance What is it what does it do? Collosus has 8uH!
Replies: 308
Views: 31834

Re: Inductance What is it what does it do?

OK SOOOOOOOOOOOOOOOOOOOOOOOOOOOO BIIIIIIIIIIGGGGGGGGGGG NEEEEEEEEEEWWWWWWWWWS. Collossus has such low inductance it midas well not have any (well ok almost) I got the first cheep inductance meter today and here is some findings.... OH BTW you guys rewinding motors that are hard to control you would...
by Lebowski
Aug 04 2011 1:01am
Forum: General Discussion
Topic: I'd like to go to college for electrical engineering
Replies: 23
Views: 1867

Re: I'd like to go to college for electrical engineering

I'm also an EE, I studied analog circuit design for implementation on IC's. For work I make things like ADC's for radio signals or DAC's with integrated amplifier for headphones. I like to think I'm very good at my job, I'm the top engineer at my site of work, I presented papers at international con...
by Lebowski
Aug 03 2011 5:46am
Forum: E-Bike Technical
Topic: I'm uncertain about the efficiency of Geared vs Direct Drive
Replies: 14
Views: 1677

Re: I'm uncertain about the efficiency of Geared vs Direct D

for a radial fluxm motor with no iron core: P_loss/P_usefull is proportional to 1 / (engine_rpm)^2 And with engine I mean the magnet/coil bits. But also P_loss/P_usefull is proportional to 1 / engine volume So.... it all depends :) a geared motor is typically build to a smaller form factor but runs ...
by Lebowski
Jul 27 2011 1:15am
Forum: E-Bike Technical
Topic: Converting a cargo tricycle (bakfiets)
Replies: 29
Views: 3639

Re: Converting a cargo tricycle (bakfiets)

Hoi bakfiets, ook een Nederlander ? Engine speed is a big factor regarding the efficiency of an engine. With 'engine speed' I mean the speed of the magnet/coil bits. It's a quadratic relation so 2 times the speed reduces the losses to 1/4. This is why hub motors are in general a bad idea if you go s...
by Lebowski
Jul 21 2011 2:02am
Forum: Motor Technology
Topic: My homemade bicycle motor, version 1
Replies: 8
Views: 4945

My homemade bicycle motor, version 1

Since I was pulling apart my motor anyway I thought I'd make some pictures to show how it's built. The motor is meant to power a bicycle. Here in Switzerland the limit for electric bikes is 250 W, above that it doesn't count as a bicycle anymore and it gets messy in the legal department (you need a ...
by Lebowski
Jul 20 2011 3:58am
Forum: E-Bike Technical
Topic: Excess current draw.
Replies: 19
Views: 2126

Re: Excess current draw.

Maybe the iron in your motor is saturating ? This would cause a sudden drop in winding inductance (which in turn leads to a sharp current increase)...
by Lebowski
Jul 20 2011 3:13am
Forum: Battery Technology
Topic: watt hours in series vs parallel - discuss
Replies: 17
Views: 2058

Re: watt hours in series vs parallel - discuss

Ok, I see your point, my reply was based on two different motors (the 100V one having 4 times more windings as the 25V one to
achieve same rpm, based on the simple PWM controllers everyone seems to use)
by Lebowski
Jul 20 2011 1:41am
Forum: Battery Technology
Topic: watt hours in series vs parallel - discuss
Replies: 17
Views: 2058

Re: watt hours in series vs parallel - discuss

Interestingly, the phase current only depends on the rate the motor is spinning and the power entering it. So, your 100v pack and your 25v pack both dumping 500w into the motor at the same speed both are placing exactly the same phase current on the motor and need the same size wires. The higher vo...
by Lebowski
Jul 08 2011 10:58am
Forum: Motor Technology
Topic: Agni motor tuning and racing
Replies: 123
Views: 25242

Re: Agni motor tuning and racing

Ok I get your argument regarding that the speeds (or to put it better: the pwm dutycycle) of the two controllers must match... How about splitting the output MOS transistors down the middle ? Example: lets say your controller has 6 MOS transistors in parallel capable of supplying enough current for ...
by Lebowski
Jul 08 2011 10:47am
Forum: E-Bike General Discussion
Topic: So, I pitched the idea of E-bikes to the local bicycle cops
Replies: 73
Views: 4913

Re: So, I pitched the idea of E-bikes to the local bicycle c

I bet you the police said something in the order of: "OK dude so you want to provide the local kids with fast e-bikes so us bicycle cops can no longer catch them ?"

followed by a good beating :mrgreen: jailtime :shock: sodomy :|